Absence of cytochrome P-450 and presence of autolysosomal membrane antigens on the isolation membranes and autophagosomal membranes in rat hepatocytesA Yamamoto, R Masaki, Y Fukui and Y Tashiro Department of Physiology and Cell Biology, Kansai Medical Center, Osaka, Japan. We wished to determine if phenobarbital (PB)-inducible cytochrome P-450 [P-450(PB)] and autolysosomal membrane antigens could be localized immunocytochemically on the isolation membranes and the limiting membranes of autophagosomes in rat hepatocytes by the post-embedding protein A-gold method. P-450(PB) was maximally induced by PB treatment; then formation of autophagosomes and accumulation of autolysosomes were induced by cessation of PB treatment and by injection of leupeptin, respectively. P-450(PB) was detected neither on the isolation membranes nor on the limiting membranes of autophagosomes and autolysosomes. Autolysosomal membrane antigens, which were localized by the immunogold technique exclusively in post-Golgi compartments such as lysosomes, endosomes, and plasma membrane but were not found in pre-Golgi compartments such as endoplasmic reticulum (ER) and nuclear envelope, were detected in large amounts on the isolation membranes. These results suggest that the isolation membranes originate not from ER membranes but from post-Golgi membranes. We also present direct immunoelectron microscopic evidence that P-450(PB) is indeed degraded in the autolysosomes: when rats were treated with leupeptin, P-450(PB) was detected not only within the autophagosomes but also within the autolysosomes, whereas without leupeptin treatment, P-450(PB) was detectable only within the autophagosomes.
Volume 38,
Issue 11,
pp. 1571-1581,
11/01/1990
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N. Ishihara, M. Hamasaki, S. Yokota, K. Suzuki, Y. Kamada, A. Kihara, T. Yoshimori, T. Noda, and Y. Ohsumi Autophagosome Requires Specific Early Sec Proteins for Its Formation and NSF/SNARE for Vacuolar Fusion Mol. Biol. Cell, November 1, 2001; 12(11): 3690 - 3702. [Abstract] [Full Text] [PDF] |
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O. Muller, T. Sattler, M. Flotenmeyer, H. Schwarz, H. Plattner, and A. Mayer Autophagic Tubes: Vacuolar Invaginations Involved in Lateral Membrane Sorting and Inverse Vesicle Budding J. Cell Biol., October 23, 2000; 151(3): 519 - 528. [Abstract] [Full Text] [PDF] |
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T. Sattler and A. Mayer Cell-free Reconstitution of Microautophagic Vacuole Invagination and Vesicle Formation J. Cell Biol., October 23, 2000; 151(3): 529 - 538. [Abstract] [Full Text] [PDF] |
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T. Kirisako, M. Baba, N. Ishihara, K. Miyazawa, M. Ohsumi, T. Yoshimori, T. Noda, and Y. Ohsumi Formation Process of Autophagosome Is Traced with Apg8/Aut7p in Yeast J. Cell Biol., October 18, 1999; 147(2): 435 - 446. [Abstract] [Full Text] [PDF] |
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T. Ueno, K. Ishidoh, R. Mineki, I. Tanida, K. Murayama, M. Kadowaki, and E. Kominami Autolysosomal Membrane-associated Betaine Homocysteine Methyltransferase. LIMITED DEGRADATION FRAGMENT OF A SEQUESTERED CYTOSOLIC ENZYME MONITORING AUTOPHAGY J. Biol. Chem., May 21, 1999; 274(21): 15222 - 15229. [Abstract] [Full Text] [PDF] |
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